TIME magazine’s environment and energy correspondent Bryan Walsh reveals the extent to which the world economy relies on carbon-intensive coal for energy and argues against the use of Carbon Capture and Storage technology.

Solar, wind, biofuels and other renewable sources of energy get the hype, but there's no getting around the fact that most of our electricity still comes from fossil fuels. About half the U.S.'s electricity and 40% of the world's power comes from carbon-intensive coal. That's bad news for the climate—coal is the single-biggest source of manmade greenhouse gas emissions in the world.

It's also why the development of effective Carbon Capture and Storage (CCS) projects—power plants that could filter the greenhouse gases usually emitted by burning coal and prevent that carbon from reaching the atmosphere—could make the difference for climate change. James Fallows put it well in a cover story for the Atlantic last year, "One is that coal can be used in less damaging, more sustainable ways than it is now. The other is that it must be used in those ways, because there is no plausible other way to meet what will be, absent an economic or social cataclysm, the world's unavoidable energy demands."

Safety

"A sudden release of carbon dioxide from a volcanic lake in Cameroon in 1986 smothered over 1,200 people while they slept"

The technological and economic challenges of CCS are immense, though. Not only do we have to figure out how to filter carbon emissions in the same way we've learned to filter traditional pollutants like sulfates or ash, but we also need to find a place to safely store hundreds of millions of tons of carbon gas underground. We're not even sure yet that CCS is safe—if massive amounts of carbon dioxide escaped from the ground in an accident, it could pose a major health threat. A sudden release of carbon dioxide from a volcanic lake in Cameroon in 1986 smothered over 1,200 people while they slept. Is CCS potentially dangerous?

Thankfully, it looks not. In a new study published in the September 12 Proceedings of the National Academy of Sciences, researchers led by Stuart Haszeldine of the University of Edinburgh tallied the number of human deaths near 286 sites in Italy and Sicily where carbon dioxide naturally seeps from the ground because of volcanic activity. They found that the risk of death from CO2 leakage was just 1 in 100 million—some 10,000 times less than the chance of being killed in a car accident in Italy, for example, which if you've experienced Italian traffic, actually seems kind of low.

"Our findings show that storing CO2 underground is safe and should allay any concerns that the technology poses a significant threat to health." said Haszeldine.

"people tend to emphasize—perhaps overemphasize—the risks of new and unknown energy projects, especially if they're nearby"

So that's good news, though I suspect that if CCS plants were really put into place, there would still be significant public resistance, especially among those living near carbon storage sites. As the debate over shale gas fracking shows, people tend to emphasize—perhaps overemphasize—the risks of new and unknown energy projects, especially if they're nearby. Still, the PNAS study indicates that there doesn't seem to be much to worry about.

Cost

But safety is one thing—cost is another. There have only been a few pilot CCS projects developed so far—mostly in Europe, where a price on carbon exists—and right now the process seems to add 15-20% to the overall price tag. That's hardly cheap. And there are additional questions about where we might store billions of tons of carbon underground, and how difficult it might be to build all the additional infrastructure—think pipelines to move carbon from power plants to storage sites—around the world.

Most of all, money channelled to CCS is money that isn't going to renewables, as Stan Blackley of Friends of the Earth told the BBC, "The technology of CCS is as yet unproven at any commercial scale. We are concerned that CCS will be used as an excuse by the energy industry to develop new fossil fuel-fired power stations."